In the magnetic recording media (hereinafter referred to as the magnetic tapes) for audios, VTRs, computers and the like, there has recently an increasing demand for high-density recording in particular, and the magnetic tapes using ferromagnetic alloy powders are being produced. Furthermore, in order to improve the output in a high-frequency range, the ferromagnetic alloy powders should be more finely granulated, and the magnetic layers should be smoothened on the surface.
However, considerable difficulty is involved in uniform dispersion of the finely granulated ferromagnetic powders. Besides, finishing the magnetic layer's surface to a high smoothness causes an increase in the coefficient of friction, resulting in deterioration of the running characteristics. To add to this, such tendency becomes more prominent, as the powder becomes finer and finer.
In order to provide a solution to the aforesaid problems, heretofore, studies have been made of kneading methods (double ball mills, triple ball mills, pebble mills, high-speed mixers, etc.), addition of dipsersing agents and the like. However, there is not yet developed any method which sufficiently copes with higher performance demanded for the magnetic tapes.